Menu

Update Pidgin IM status on Ubuntu using cron

At work we use a Jabber instant messenger (IM) server for internal company communications, so that regardless of whether someone is in the office, working from home, or on the road, they can be reached via IM.

I’m running Ubuntu both at work and at home and I use the Pidgin IM client to talk to the Jabber server. I work from home on Thursdays, and I’m always forgetting to turn Pidgin off when I leave work on Wednesday. I usually end up ssh-ing into my work box from home and killing the Pidgin client off remotely, but sometimes I forget and when I come back to work on Friday there are a half-dozen “Are you there?” -type messages on my Pidgin work-client.

So I figured I’d automate the process, automatically setting Pidgin status to “Away” and “Available” using cron, turning the work-client off entirely on Thursdays and weekends, and automatically turning the home-client on Thursday mornings and off Thursday night.

I did a little digging and found a command-line program called purple-remote that allows me to automatically update the Pidgin status and message lines. The purple-remote program is included in the libpurple-bin package, which I installed with System > Administration > Synaptic Package Manager.

Once purple-remote was installed, I fired up a terminal and did a little experimenting on the command line. I found I could set Pidigin’s status to “Away” and the status message to “At lunch” by typing:

/usr/bin/purple-remote "setstatus?status=away&message=At lunch"

I could set the status to “Available” and blank the status message by typing:

This would start Pidgin at 8:00am, set my status to “Away” at 8:01am, “Available” at 9:00am, “Away – At lunch” at 1:30pm, “Available” again at 2:30pm, “Away” at 5:30pm. On Wednesday and Friday nights at 7:00pm the client shuts down entirely, on Monday and Friday mornings Pidgin gets restarted. That will leave the client off all day on Thursdays and on weekends when I’m not at the office. If my schedule changes for any reason I can still update my status in Pidgin manually.

Looks good, but this doesn’t work. Although the commands listed above work just fine on the command line, they’d fail when they were executed from cron. Checking my mail I found error messages like this:

The key part of that message is “dbus-launch failed to autolaunch D-Bus session: Autolaunch error: X11 initialization failed.” dbus is a messaging system, and X11 is the implementation of X-Windows Ubuntu uses, which is what the Gnome desktop runs on. Pidgin is an application running on the Gnome desktop / X-Windows. The error message is saying that the program failed to send a message to X11 (X-Windows) and on to Pidgin.

In order to start Pidgin at 8:00am Pidgin needs to know the value of the of the XAUTHORITY environment variable otherwise it won’t be authorized to start up on a screen that I’m logged into.

In order to start Pidgin at 8:00am Pidgin needs to know the value of the DISPLAY environment variable so it knows what screen to start up on.

When you start up Ubuntu the dbus daemon starts up and creates a unique session address. Your applications have to know this session address in order to send messages using the daemon. The address is stored in the DBUS_SESSION_BUS_ADDRESS environment variable when you log in, so if you try to run an application from the command line it gets the session address from the DBUS_SESSION_BUS_ADDRESS environment variable. Since cron runs in it’s own environment it doesn’t know the value of DBUS_SESSION_BUS_ADDRESS, so programs that depend on dbus fail when you try to run them from a cron job.

Create this script, type chmod 700 ~/bin/export_x_info so you can execute it, then execute it, then add it to System > Preferences > Sessions > Startup Programs so it will execute every time you start your computer and record the latest session address and XAUTHORITY value.

This script creates a 4-line file ~/.Xdbus with the current session address and XAUTHORITY value. By sourcing this file in the crontab file your scripts can now use dbus to send messages to X-Windows applications. My final crontab file looks like this:

Glad you found this useful. I just installed Skype at home and at work and found that this technique also works for starting up Skype, so if someone calls my Skype phone the computer where I’m located is the one that currently has Skype running.

Good solution, that’s much simpler. However, DBUS can leave old files in place in that directory (after a system crash, for example), so you want to make sure you’re sourcing the latest file. You could do something like:

For a multi-user system, i have include this script in /etc/gdm/PreSessions for create the file each users. it works.
But i’m surpised: i have a system routine with fcron (fcrontab -e -u systab), also the “shutdown -P now” works for all users, the notification message doesn’t work.. have you any idea please?
Thanks,
Regards from France,
Philippe.